ASME SA533 Type B Class 1 Steel Plate | SA533 Gr.B Cl.1 Mn-Mo-Ni Vessel Plate

ASME SA533 Type B Class 1 is the manganese-molybdenum-nickel, quenched-and-tempered vessel combination in ASME SA-533/SA-533M that uses Type B chemistry and the Class 1 strength table. The current specification lists five Types (A, B, C, D, E) and three Classes (1, 2, 3). Type tells the alloy. Class tells the tensile window.
Type A is Mn-Mo with no nickel requirement. Type B adds nickel at about 0.40–0.70% heat analysis. Type C is higher nickel. Type D is lower nickel. Type E has tighter residuals. Class 1 is the 550–690 MPa tensile window with 345 MPa minimum yield. Class 2 is 620–795 MPa and 485 MPa yield. Class 3 is 690–860 MPa and 570 MPa yield, with a 65 mm cap on Types A through D. As Direct Mill Supply by SHH STEEL, the plate is produced to ASME SA-533/SA-533M.
The same plate is written SA533 Type B Class 1, SA533 Gr.B Cl.1, SA533 Grade B Class 1, SA533GRBCL1, SA533 B Cl.1, SA-533 Type B Cl.1, ASTM A533 Type B Class 1, A533 Gr.B Cl.1 and A/SA533 Type B Class 1. The standard text says Type. Buyers and nuclear specifications still search Grade B Class 1. They mean the same plate. This is the combination most often named for reactor vessels and other heavy Mn-Mo-Ni QT shells.
Do not ship Type A and call it Type B. Type A has no nickel line. Do not ship Class 2 and call it Class 1. Class 2 is a different tensile table. Do not treat this page as SA302 Gr.B or A302 Gr.B. SA302 Grade B is normalized Mn-Mo. SA533 Type B Class 1 is quenched and tempered Mn-Mo-Ni. Same family on paper, different heat treatment, different Code line.
This is not SA516 Gr.70 or A516 Gr.70. Those pages are fine-grain carbon. It is not SA515 Gr.70. It is not SA285 Gr.C or A285 Gr.C. It is not SA537 Cl.1 or SA537 Cl.2. SA537 is heat-treated C-Mn-Si. It is not SA517 Gr.Q or SA517 Gr.B. SA517 is a different QT alloy family. It is not nickel cryogenic plate like SA203 Gr.A or SA203 Gr.D. SA203 lives on 2.25Ni or 3.5Ni without the Mo-QT route. It is not Cr-Mo like SA387 Gr.22 Cl.2.
The steel shall be killed and shall meet fine austenitic grain practice under ASME SA-20. Plates are quenched and then tempered at not less than 595 °C (1100 °F), with a minimum hold of 0.5 h/in. (1.2 min/mm) and not less than 0.5 h. As-rolled SA533 is crack-sensitive in transit, especially above about 25 mm, and may ship as-rolled only by written agreement.
Current practice normally limits Type B Class 1 to about 300 mm. Class 3 on Types A–D is capped at 65 mm. Minimum nominal thickness is 6.5 mm.
For Code work the plate is used under ASME Section VIII, and in nuclear work it is often tied to additional purchaser specifications beyond SA-533 itself. Dual marking ASME SA533 Type B Class 1 / ASTM A533 Type B Class 1 is available. Certificates can be EN 10204 3.1 or EN 10204 3.2.
When a project is still choosing QT vessel plate, a China mill Agent path through SHH STEEL puts SA533 Type B Cl.1 next to SA302 Gr.C, SA537 Cl.1 and A36 steel plate, so the buyer can see whether they need QT Mn-Mo-Ni, normalized Mn-Mo-Ni, heat-treated carbon or structural carbon. Company scope: China steel Mill Agent-SHH STEEL.

This plate is a vessel product. It is not structural ASTM A36 steel plate. It is not SA516 Gr.60. It is not SA285 Gr.A.

Chemistry for ASME SA533 Type B is the Type table. Class 1, Class 2 and Class 3 share Type B chemistry unless Supplementary Requirement S3 is used to raise manganese on Class 2 or Class 3.

Heat Analysis — ASME SA533 Type B

Product Analysis — SA533 Gr.B / A533 Type B

Nickel is the Type B marker. Type A has no nickel requirement. Type C heat nickel is about 0.70–1.00%. Type D heat nickel is about 0.20–0.40%. A Type A ladle cannot be stamped Type B. A Type C ladle cannot be stamped Type B because the nickel window is different.

For Class 2 and Class 3, the specification allows manganese maximum to 1.60% heat and 1.65% product when S3 is specified. That option is not automatic on Class 1.

Compare that ladle with SA302 Gr.B (normalized Mn-Mo, no Ni on Grade B), SA302 Gr.C (normalized Mn-Mo-Ni), SA387 Gr.11 Cl.2 (Cr-Mo) and SA516 Gr.70 (carbon). None of those tables is SA533 Type B.

If the drawing says ASME SA533 Type B Class 1 or SA533 Gr.B Cl.1, the ladle must sit in the Type B table and the tensile test must sit in the Class 1 window. SHH STEEL reports heat analysis on every certificate, including nickel and molybdenum, and adds product analysis when SA-20 requires it.

Nuclear or high-restraint orders often add residual limits beyond Table 1. Those limits are supplementary. They are not assumed because the plate is Type B Class 1.

Class 1 is the strength line. Type B only tells the alloy.

Tensile Requirements — ASME SA533 Class 1

Class 2 is 620–795 MPa and 485 MPa yield, with 16% elongation. Class 3 is 690–860 MPa and 570 MPa yield, with 16% elongation and a 65 mm cap on Type B. A Class 1 heat cannot be stamped Class 2 because someone wants the higher name.

Density is 7.85 g/cm³. Hardness is not a default line. Charpy is not a hidden default in SA-533. Reactor-vessel and thick-wall Class 1 work almost always writes drop-weight, Charpy temperature, location and orientation as extras. Those extras belong on the purchase order.

Compare SA537 Cl.1 and SA517 Gr.Q. Overlap on a number is not a substitute.

Order ASME SA533 Type B Class 1 when the drawing names Type B and Class 1. SHH STEEL does not swap this plate for A516 Gr.70 or A517 Gr.Q.

ASME SA533 Type B Class 1 is selected for welded vessels that need QT Mn-Mo-Ni strength at the Class 1 window. This is the combination most often named for nuclear reactor vessels, steam-generator related shells and other heavy-wall Mn-Mo-Ni equipment. Allowable stress comes from ASME Section II Part D for SA-533 Type B Class 1. Nuclear purchasers usually add a project specification on top of SA-533.

Typical use is heavy-wall process vessels, reactor shells specified to SA-533 Type B Class 1, and dual-certified export plate. If the drawing says Type A, there is no nickel. If the drawing says Type C, nickel is higher. If the drawing says Class 2, tensile and yield both rise.

It is not a replacement for SA387 Gr.91 Cl.2 creep service or SA203 Gr.E nickel low-temp service.

SA533 Gr.B Cl.1 is QT Mn-Mo-Ni. Welding is Code welding, not structural fillet practice from ASTM A36 steel plate.

Procedures are qualified to ASME Section IX. Low-hydrogen practice is mandatory. Consumables must match the required joint strength and toughness after any PWHT. Carbon can sit at 0.25%. Molybdenum is in the 0.45–0.60% heat band. Nickel is in the 0.40–0.70% heat band. Calculate carbon equivalent from the actual ladle.

Preheat depends on thickness, restraint, hydrogen and the qualified WPS. Thick Class 1 plate is not a 12 mm carbon fillet. After welding, many shops want to PWHT. Simulated PWHT of mill coupons should be on the purchase order when the vessel cycle is known.

Do not copy a SA387 Gr.22 Cl.1 Cr-Mo procedure or a SA517 Gr.A QT procedure onto Type B Class 1 without review. The fabricator owns the WPS.

Plates shall be quenched and tempered.

Tempering shall be at a suitable temperature to produce the specified Class 1 properties, but not less than 595 °C (1100 °F), with a minimum holding time of ½ h/in. (1.2 min/mm) and not less than ½ h.

As-rolled delivery is not the specified condition. As-rolled shipping is crack-sensitive above about 25 mm and requires written agreement. SHH STEEL reports quench and temper temperatures and holds on the MTC for every SA533 Type B Class 1 plate.

Do not apply the normalize-only route used for SA302 Gr.B and call the plate SA533 Type B Class 1.

Usual delivery is quenched and tempered Type B Class 1 plate.

The certificate lists ASME SA533 Type B Class 1 and, when dual certified, ASTM A533 Type B Class 1; heat number; heat analysis including Ni and Mo; product analysis when ordered; tensile results to the Class 1 table; QT temperatures; Charpy results when ordered; and supplementary tests.

Certificates may be EN 10204 3.1 or EN 10204 3.2. BV, LR, DNV, TUV, SGS or the buyer’s agency can witness rolling, quenching, tempering and testing when the order says so.

Usual supply range from SHH STEEL for SA533 Gr.B Cl.1 Mn-Mo-Ni vessel plate:

• Thickness: 6.5 mm – about 300 mm for Class 1 (current practice on Type B)
• Width: up to about 4000 mm
• Length: up to about 12000 mm

Class 3 is not this page. Class 3 on Type B stops at 65 mm.

Dimensional limits follow ASME SA-20. Thickness, width, length, flatness and camber are vessel-plate tolerances.

Ultrasonic testing to A435, A577 or A578 is commonly added on thick QT plate, and is expected on nuclear-related orders.

Most export ASME SA533 Type B Class 1 orders add extras. SHH STEEL does not assume them.

Charpy and drop-weight. Temperature, energy, location, orientation. Reactor and thick-wall work almost always writes this.

Simulated PWHT. Same-heat coupons follow the vessel cycle.

NDE. UT to A435 / A577 / A578; edge MT/PT after cutting.

Restricted residuals. When nuclear or high-restraint work specifies them.

Restricted P, S. Tighter than 0.025% when specified.

Third-party. Witness of QT and testing. Output can be EN 10204 3.2.

If an item is not on the purchase order, it is not assumed.

For stamping, write ASME SA533 Type B Class 1 or dual SA533 / A533 Type B Class 1.

Do not use this grade as a silent stand-in for SA203 Gr.B or SA517 Gr.S.

SHH STEEL works as a China Mill Direct Exporter for plates to ASME SA-533/SA-533M. On ASME SA533 Type B Class 1 that means mill pricing, dual SA533/A533 marking, Type B chemistry with nickel in the 0.40–0.70% heat band, recorded quench and temper, Class 1 tensile results at 550–690 MPa and 345 MPa yield, 3.1 as standard and 3.2 when specified.

We keep the order on the right Type and Class. Type B is not Type A. Class 1 is not Class 2. SA533 is not SA516 Gr.55. SA533 is not SA285 Gr.A. SA533 Type B Cl.1 is not SA517 Gr.Q. If the drawing names normalized Mn-Mo-Ni, we point the inquiry to SA302. If it names Type A, we will not ship Type B and call the nickel “close.”

Company scope: China steel Mill Agent-SHH STEEL.

ASME SA533 Type B Class 1 Steel Plate is quenched-and-tempered manganese-molybdenum-nickel vessel plate under ASME SA-533/SA-533M. Whether the inquiry says SA533 Type B Class 1, SA533 Gr.B Cl.1, SA533 Grade B Class 1 or A533 Type B Class 1, SHH STEEL supplies plate with Type B chemistry, recorded QT, Class 1 tensile results, and EN 10204 3.1 or 3.2 certification.

As a China mill Distributor, SHH STEEL provides ASME SA533 Type B Class 1 / SA533 Gr.B Cl.1 Mn-Mo-Ni Vessel Plate for ASME Section VIII and heavy-wall QT work.

Contact SHH STEEL for mill rolling, dual SA533/A533 marking, 3.2 inspection or a quotation.

ASME SA533 Type B Class 1 Steel Plate, SA533 Gr.B Cl.1, SA533 Grade B Class 1, ASTM A533 Type B Class 1, Mn-Mo-Ni QT vessel plate, Direct Mill Supply by SHH STEEL